Such a spout is known from DE 10 2008 034 595 A1. With this known spout, the sealing stopper forms a drinking tube that can be raised by the closure cap and has openings at the side, so that after the drinking tube has been raised, it can be held in one's mouth to allow the liquid in the container to flow into one's mouth, in particular to suck it out. This known design has a tamper-indicating ring beneath the closure cap, such that it is broken open when the closure cap is unscrewed. The tamper-indicating ring is difficult to see due to its position beneath the closure cap, so that it is not always possible to ascertain immediately whether the closure has already been opened. When the closure cap is twisted off, the drinking tube can be rotated, so that it is impossible to achieve an absolutely secure seal.